: 68 Coupe Deville with donor engine.

02-21-13, 11:23 PM
This is my first post but have been reading a lot from this forum for the last couple weeks. I recently bought a 68 CDV that had been sitting since 1990. I got it running but it seems to still be running a little funky. It will start fine, idle fine and warm up good but when I rev it up and open the secondaries, it seems to be dumping a lot of fuel and spits it up through the top of the carb and bogs a lot. It will not really accelerate anymore and uses a lot of fuel. Any info into what might be my problem would surely be helpful. Another thing. I'm not exactly sure if its a 472 or a 500 or the year of the engine. I ran a search of the casting numbers on the block but didn't get any specific information, as a matter of fact I read a lot of contradictory info that just confused me and made my head hurt. Any info on this would be appreciated also.


The casting number on the passenger side rear of the engine by the bell housing is 1495200

The stamped number on the driver side in the same location is 610222750

If this helps, thanks.

02-22-13, 01:44 AM
I'd start with a carb rebuild. Whether it's a 472 or 500 (1968 should be the 472), it's not going to be great on gas. Expect about 10mpg around town and maybe 14 on the highway.

02-22-13, 09:30 AM
I put a rebuilt fresh rebuilt carb on it already, the one that was on it was gummed up so bad. This is the new one I'm having problems with

02-22-13, 12:16 PM
Where did that carb come from? I've heard the generic rebuilt ones from the parts stores can be total junk. There are a few places that specialize in properly rebuilding quadrajets. I just sent money out to another board member that took his professionally rebuilt off. My recently acquired 68 has been having problems with stalling and major flooding out at idle. Surprisingly over last couple trips it has not done it once!

02-22-13, 01:35 PM
I went through a place called carb exchange, they sent me a rebuilt carb with a paid return postage sticker. When I received it, I put my junk one in the box and sent it back. I called the tech guy and told him what I'm having issues with and he is gonna send me a different one right away. But in the mean time I would like to try to figure it out. It may not be a carb issue, the mechanic where I work said it could be vacuum problem related. Still looking for info on how to determine what year engine I have in my car as well. Just for reference on the factory performance numbers and compression and so on. When ordering parts I would like to be able to ask for the right stuff.

02-22-13, 04:59 PM
Hard to say but I looked up some information about these carbs and came across a website where a rebuilder went into detail on what some of these assembly line carb rebuilder places do and it was pretty scary.

02-22-13, 08:55 PM
The research I have done has lead me to believe my engine is a 71. I'm going t check the stroke this weekend to see if its a 472 or a 500.